Brake disc and hub combination

ABSTRACT

A brake disc for use in a disc brake and a method of manufacture thereof is characterized in that the bell and annulus are separately manufactured with complementary abutting datum surfaces and are engaged together by projections on one which mesh in slots to hold the two members together against relative axial and rotational movement. Preferably the projections engage the sides of the slots and not the roots so that there is some rotational preloading. The projections can be provided on a continuous or discontinuous skirt integral or welded to the bell and the slots are on a surface of the annulus opposite to the datum face thereof. The projections may be partially sheared from a continuous skirt.

O United States Patent [151 3,661,235 Harrison 51 May 9, 1972 1 BRAKEDISC AND HUB COMBINATIO 2,233,594 3/1941 Eksergian ..188/264 A x2,656,730 10/1953 Mitchell.... [72] Inventor. Anthony William Harrison,Blrmmgham, 2,926,760 3/1960 Lucien England 3,542,166 11/1970 Harrison..188/218 x1. [73] Assignee: Girling Limited, Birmingham, EnglandPrimary E.\'aminer-Ge0rge E. A. Halvosa Flledi 1970 Attorney-Scrivener,Parker, Scrivener and Clarke [21 1 Appl. No; 20,359 ABSTRACT A brakedisc for use in a disc brake and a method of manufac- [301 ForelgnAppl'canon pnomy Data ture thereof is characterized in that the bell andannulus are Man 22, 1969 Great Britain 15,173/69 separatelymanufacturedwith complementary abutting datum July 4, 1969 Great Britain..33,747/69 Surfaces are engaged Ogether by PmJectwnS 9 which mesh inslots to hold the two members together agamst relative axial androtational movement. Preferably the projecg 'i Ass/218x14 F LgZ tionsengage the sides of the slots and not the roots so that 1] nt. there issome rotational preloading The projecfions can be [58] held of Search218 264 provided on a continuous or discontinuous skirt integral or188/264 AA; 192/107 R1 1 13 A; 29/512 welded to the bell and the slotsare on a surface ofthe annulus 159 15931 470's opposite to the datumface thereof. The projections may be partially sheared from a continuousskirt. [56] References Cited UNITED STATES PATENTS 9 Claims, 11 DrawingFigures 2,013,805 9/1935 McIntosh ..29/512 X 1 BRAKE DISC AND I-IUBCOMBINATION INTRODUCTION The present invention concerns a brake disc,that is, the rotating part of a disc brake which is to be contacted withopposed friction pads by suitable means to arrest say, a vehicle.

As is well known, a brake disc comprises a hub part, sometimes calledthe bell, and an annulus provided with the braking surfaces. In thisspecification bell and annulus are used to mean these parts.

Problems are encountered with thermally induced distortion and thermallyinduced cracking of brake discs. To overcome these problems, expensiveconstructions of brake discs have been devised.

The object of the present invention is to minimize the cost andcomplexity of brake disc construction.

The present invention in one aspect provides a brake disc comprising abell member and a separate annulus member which abut each other on adatum face and are held thereagainst by a skirt on one member,circumferentially spaced projections from this skirt meshing in slots inthe other member to hold the two members irrotationally.

According to another aspect of the present invention, there is provideda method of making a brake disc for a disc brake comprising placing abell member and an annulus member in abutting relationship and deforminga skirt on one of said members around the other member to hold themembers together and into slots in the other member to hold the membersrelatively irrotational.

This construction can be used with a braking annulus of either the solidor ventilated type.

Embodiments of the present invention, will now be described, by way ofexample, with reference to the accompanying drawings.

IN THE DRAWING FIG. 1 is a side view half in section of a firstembodiment of the brake disc,

FIG. 2 is a sectional detail of the embodiment shown in FIG.

. FIG. 3 is a further detail of the embodiment of FIG. 1 taken at rightangles to the detail of FIG. 2 along line lII-III,

FIG. 4 is a side view half in section of a second embodiment,

FIG. 5 is an enlarged detail of part of FIG. 4,

FIG. 6 is an enlarged detail of a cross-section of FIG. 5 along lineVI-VI of FIG. 5,

FIG. 7 is a detail axial section of the connection between a bell and anannulus in a first stage of manufacture of a third embodiment,

FIG. 8 is a similar detail in a second stage of manufacture showing aforming tool,

FIG. 9 is a third stage of manufacture showing another tool,

FIG. 10 is a developed view on the line of arrow 31 in FIG. 10, and

FIG. 11 is a developed view on the line of arrow 31 in FIG. 10 butshowing a final press tool operation.

The specific embodiments have a bell or hub portion 11 and an annulus 12which are interengaged by projections 13 from the bell which engage inslots 17 in the annulus. The annulus has vanes 14 to create a flow ofair through a hollow interior 15 of the annulus to cool the annulus. Theannulus is cast. It will be appreciated that the annulus illustratedconsists of the bare essentials namely, side walls 16 and cooling vanes14. The slots 17 are defined between the vanes 14 but with uncooledbrake discs or if desired for other reasons the slots 17 can be machinedin the annulus. The bell can be a simple pressing and has four holes 18by which it is to be attached to a shaft or wheel which is to be braked.

It is of course obvious that the annulus has got to be machined toprovide braking surfaces 19 and also a datum face 20. Similarly, thepressed bell has also to be machined to provide a datum or true runningface. In FIG. 2 the bell datum face is a shoulder 21a machined onto thebell but in FIG. 5 it is a machined end 21!: of the bell. The slots arein a face of the annulus that faces in the opposite direction to thedatum face on the annulus.

In FIG. 2 the projections 13 are formed in a skirt 13a integral with thebell and are in the form of castellations extending axially from thebell initially and defined by notches or like discontinuities butsubsequently deformed into the slots 17 between the vanes 14. Theprojections are initially wider than the slots so that the projectionswhen urged into the slots deform partially elastically into the arcuateshape shown in FIG. 3 and provide a resilient loading of the annulusagainst the bell. Moreover since the forces on the annulus exerted bythe projections have components in a circumferential direction, there isa measure of circumferential pre-loading which ensures that there is notendency for the annulus to move angularly relative to the bell.

In the embodiments of FIGS. 4 to 6 instead of the bell being a simplepressing, the bell comprises a simply pressed part Ila and a strip 11bof material. The strip has notches 23 punched out along one of its edgesso as to leave the castellations or projections 13 between these notchesand the strip is preformed so as to have the projections curved up.After fitting the bell part Ila to the annulus, this strip is sprung orotherwise located as shown and is clamped hard against the annulus sothat the projections tend to straighten while the strip is electricallyspot welded 24, or otherwise joined to the part 11a to form the skirt ofthe composite bell. Afterwards the projections will try to regain thecurvature and will exert a resilient pre-loading. In these figures thestrip is made so that the projections are narrower than the widths ofthe slots in which they fit but because of the curved roots entailed bycasting the effect is virtually the same as in FIGS. 1 to 3. If theroots were sharper, the projections would have to be broader than theslots, so that the projections would engage on the vanes themselves.

The strip 11b need not be continuous but could be a plurality of arcuatelengths of strip. Particularly with machined slots where the roots ofthe slots may be sharp edged, the slots can have tapered sides to give aradial and a circumferential reaction force between the sides of theslot and the projections where the projections contact the sides, thatis at the comers of the projections.

Radial expansion of the annulus due to braking heat can be allowed forby relative sliding movement of the projections in the slots or by meansof slits 26 in the bell which provide a degree of radial resiliency asdescribed in our U.S. Pat. No.

In a third embodiment, the manufacture of which is illustrated in FIGS.7 to 11, slots 17 are defined on the annulus 12 by cooling vanes 14which are provided with portions 14a wherein the vanes extend a constantdistance from the plane of the annulus that is to say these portions ofthe vanes form ridges of uniform height extending from the annulus.

The bell 11 is formed with a continuous skirt I Is which initiallyextends axially into the annulus from a datum surface 21a machined onthe bell. This skirt can be homogeneous with the bell or can be a stripor arcuate lengths of strip welded or otherwise joined onto the bell asin the earlier embodiment.

The skirt is then flanged to lie over the slots by means of a suitablepress or spinning tool 29 (FIG. 8) which urges the material radiallyoutwardly in the direction of arrow 30 and then forced along arrow 31into the slots between the vane portions by a tool 32 in a projectionforming second operation (FIG. 9) which stretches the skirt locally andinto the slots by a tool 33 in a final pressing operation (FIG. 11),which at least partially shears the projections from the lands leftbetween them along at least part of the slot edges as illustrated. Itwill be found that the projections tend to spring back clear of theslots into an arcuate section in a plane transverse to the slot andcontact only the sides thereof. Because of the stretching that occurredin the second operation, the efi'ect is the same as in the precedingembodiments namely that the projection is oversize for the slot and aforce fit ensues to give a resilient pre-loading.

It will be apparent that the various forms illustrated in FIGS. 1 and 4can be modified in accordance with the procedure outlined with referenceto FIGS. 7 to 11.

Moreover it will be apparent that the slots need not be on a facetransverse to the axis of the annulus but could be on a peripheralsurface. For example, the bell could be clinched onto the annulus in oneoperation with the skirt hard against an axially transverse surface andthen the material of the skirt deformed into slots defining axialsplines or similar teeth on the interior or exterior of the annulus.

The present invention can be adapted to provide many advantages amongstwhich are:

a. the possibility of standardizing on a small range of annuli forcombination with any number of hubs or bells for differing vehicles,

b. the straightforward manner of machining the annulus bearing in mindthat deformation of projections caters for and offsets widemanufacturing errors,

c. the ease of manufacturing of the bell,

d. the manner of assembly is simple and permanent requiring only a pressoperation or welding and e. that the annulus runs true since it islocated on two flat datum surfaces.

lclaim:

1. A brake disc for use in a disc brake comprising a bell and an annulusheld together in a precise relationship, with a datum face on an axialface of the annulus pressed against a complementary datum face on thebell by a skirt extending from the bell, which skirt extends around aperipheral face of the bell into abutment with a second axial face ofthe annulus facing in the opposite direction to the first-mentionedaxial face, there being slots in the annulus and projections from saidskirt which engage in the annulus slots, characterized in that saidskirt is clenched around the inner peripheral face of the annuluswhereby on radial thermal expansion of the annulus, the annulus canslide outwardly relative to the bell rather than pushing the ball apart.

2. A brake disc according to claim 1 wherein the annulus is of the typehaving cooling vanes to ventilate the disc and wherein said slots aredefined between the cooling vanes.

3. A brake disc according to claim 1 wherein the bell member is made asa single integral pressing and the projections are an integral part ofthe bell member.

4. A brake disc according to claim 1 wherein the slots are provided onan axially transverse surface.

5. A brake disc according to claim 4 wherein the slots are in saidsecond axial face.

6. A brake disc according to claim 1 wherein the projections contact thesides of the slots and are held deformed thereby so that the projectionspress resiliently on the sides of the slots to give a resilientpre-loading.

7. A brake disc according to claim 6 wherein the projections are heldcurved transversely to the slots by the sides thereof.

8. A brake disc according to claim 1 wherein the skirt is substantiallycontinuous.

9. A brake disc according to claim 8 wherein lands left between theprojections hold the datum surfaces firmly in contact with each other.

i i i I

1. A brake disc for use in a disc brake comprising a bell and an annulusheld together in a precise relationship, with a datum face on an axialface of the annulus pressed against a complementary datum face on thebell by a skirt extending from the bell, which skirt extends around aperipheral face of the bell into abutment with a second axial face ofthe annulus facing in the opposite direction to the first-mentionedaxial face, there being slots in the annulus and projections from saidskirt which engage in the annulus slots, characterized in that saidskirt is clenched around the inner peripheral face of the annuluswhereby on radial thermal expansion of the annulus, the annulus canslide outwardly relative to the bell rather than pushing the ball apart.2. A brake disc according to claim 1 wherein the annulus is of the typehaving cooling vanes to ventilate the disc and wherein said slots aredefined between the cooling vanes.
 3. A brake disc according to claim 1wherein the bell member is made as a single integral pressing and theprojections are an integral part of the bell member.
 4. A brake discaccording to claim 1 wherein the slots are provided on an axiallytransverse surface.
 5. A brake disc according to claim 4 wherein theslots are in said secOnd axial face.
 6. A brake disc according to claim1 wherein the projections contact the sides of the slots and are helddeformed thereby so that the projections press resiliently on the sidesof the slots to give a resilient pre-loading.
 7. A brake disc accordingto claim 6 wherein the projections are held curved transversely to theslots by the sides thereof.
 8. A brake disc according to claim 1 whereinthe skirt is substantially continuous.
 9. A brake disc according toclaim 8 wherein lands left between the projections hold the datumsurfaces firmly in contact with each other.